The invention relates to the field of sheet feeding and, more particularly, to the alignment of sheets shingled and fed singly from a stack of sheets.
Feeding sheets forward from a stack by shingling or combing with a roller has been known for many years, such as shown by U.S. Pat. No. 566,670, E. Dummer, "Paper Feeding Machine." Shingling sheets by means of a wheel containing many rollers (a shingling or combing wheel) has also been known, e.g., U.S. Pat. No. 781,504, E. Dummer, "Paper Feeding Machine." In each instance, the rollers are wider than the sheets being fed and no alignment guides are provided. Alignment of the sheets has been presumed. However, the potential rotational torque effect of shingling was clearly recognized in U.S. Pat. No. 3,008,709, W. S. Buslik, "Sheet Separating and Feeding Apparatus," where torque of a shingler was employed to separate sheets by rotating the sheets.
Shingling has been employed in recent years to feed blank sheets in at least one system, the IBM 6670 Information Distributor. The shingler wheel is smaller than the width of the sheets and is not precisely centered. Alignment is not a problem because the sheet feed path is relatively long and allows considerable distance for alignment prior to entering the using transfer station.
In feeding original documents into a machine such as a copier, it is advisable to reduce the length of the paper path between adjacent stations to a minimum in order to keep the machine as compact as possible. Therefore, alignment of original documents leaving a feeder for positioning on a document glass to be scanned and copied becomes important.